How To Seal Acid Stained Concrete

Knowing how to seal acid stained concrete will help you understand how to properly enhance, protect, and maintain your new or old acid stained concrete. Most concrete sealers used on acid stained concrete are either solvent or water based acrylics. There are others, epoxies, urethanes, and penetrating, but for the most part, acrylic-based sealers are used to seal acid stained concrete.

Acrylic based concrete sealers are the easiest to apply and usually less expensive than the other sealers on the market. The important things for you to know are how to apply this sealer to acid stained concrete and what to expect from it after you or your contractor apply it.

What type of concrete sealer should I use on my acid stained concrete?

For interior acid stained concrete, a water-based acrylic concrete sealer works best. The sealer should have 20 - 25 % solids, this will allow it to breath, allow for easier application, and give you the color enhancement most people desire. For exterior acid stained concrete, a solvent-based acrylic sealer with the same solids works best.

The concrete surface preparation is very important. The surface of the concrete should have been neutralized after acid staining with a solution of 1/2 pound baking soda mixed with 5 gallons of water. After mopping this solution on the concrete and rinsing or vacuuming it off, the surface should have been rinsed at least another 2 times or until the rinse water is clean with no color. After rinsing, you should let the surface dry a minimum of 24 hrs., 48 hrs. in damp, humid conditions.

After cleaning the concrete and letting it completely dry, you're ready to apply the concrete stealer. There are a few ways to you can apply the sealer to the concrete. You can roll it on with a 3/8 inch nap lint free roller, you can spray it on with a pump up sprayer (you may need to back-roll with a roller for an even coverage), or you can use a lambs wool applicator for smooth surfaces.

The concrete sealer should be mixed with a battery drill and mixing paddle prior to pouring it in a painter's tray or a pump up sprayer. I also like to pour the concrete sealer through a piece of screen to catch any small lumps before pouring it into a sprayer. The tips on pump-up sprayers clog very easily, so screening is a must, even a coffee filter will work.

Acrylic concrete sealers for decorative acid stained concrete need to go down very thin. 1 to 2 mils thick is all you want to strive for for each application. I usually apply 2 coats minimum, 24 hours apart. The sealer must remain breathable, if it goes down too thick the sealer could turn white, foggy, or blisters and bubbles could form. Basically, you're applying what amounts to a thin sheet of plastic to the surface of the concrete to help protect it.

The best times of day and temperatures to apply decorative concrete sealers are either early morning or late afternoon with the temperature between 50 - 75 degrees F. If the temperature is too cold or too hot the sealer will dry too slow or too fast, increasing your chances of premature failure. Also remember, moisture is your enemy, if you see moisture on the surface of the concrete or if there is a chance of rain in the next 24 hours, delay applying the sealer until those issues are resolved.

Here are some tips that can help when using acrylic decorative concrete sealers if you want to achieve long term success.

1. Understand the concrete sealer is just a sacrificial coating to help enhance and protect the concrete. You will have to maintain the concrete sealer, applying a new coat as it shows wear.

2. Apply the sealer coatings very thin, most issues are from applying the concrete sealer too thick.

3. Use 20% -25% solids acrylic sealers, they breath better, enhance the color, and are easier to apply.

4. Choose a satin or matte finish, high gloss concrete sealers show scratches and imperfections much more than low gloss sealers.

5. For exterior applications the sealer will make the concrete slippery, you may want to add a non-slip additive.

6. For interior applications apply an acrylic wax over the concrete sealer. The wax will be the wear surface allowing you to maintain the wax instead of the sealer (much easier in my opinion).

7. Acrylic concrete sealers are not very good when it comes to chemical and stain resistance, be careful what you spill and wipe it up in a timely fashion.